BackgroundKit Kat is a chocolate-covered wafer biscuit bar confection created by Rowntree's of York, England, and is now produced globally by Nestlé, which acquired Rowntree in 1988, with the exception of the United States where it is made under license by H.B. Reese Candy Company, a division of The Hershey Company.
This is a very widespread Mandela Effect. Many people  remember "Kit Kat" having a hyphen in the middle, rather than a space. Most people particularly remember the hyphen being in the old Kit Kat logo. Although KitKat is manufactured by two companies - Hershey in the USA and Nestle everywhere else - the spelling still remains the same, "KitKat" with no hypen.
ResidueEvidence for this particular Mandela Effect is mostly anecdotal. All photographs of KitKat with a hyphen have been proven fake.
Nestle, the company behind the KitKat, has made an official statement on this Mandela Effect.
My colleagues tell me that there is a rumour going around that there used to be a hyphen on KitKat’s wrappers, and that it has mysteriously disappeared in recent years.
I can categorically say that the KitKat name was not hyphenated (either on the UK or US wrappers), and that the only time I have seen the name hyphenated is on one very rare wrapper from the Second World War (which I don’t have a photograph of) and on our 1920s Kit-Cat chocolate boxes.